Temperature responsive control mechanism



3 Seets-Sheet l A. J. HUCK Filed NOV. l0, 1941 N l l l l l I I l l l mwQN INVNTOR. @fred JHa/c/U, gm SM o o o o TEMPERATURE RESPONSIVE CONTROLMECHANISM Feb. 27, 1945.

Feb. 27, 1945. A. J HUCK 2,370,404

TEMPERATURE RESPONSIVE CONTROL MECHANISM Filed Nov, l0, 1941 3Sheets-Sheet 2 1N VENT OR.

@fre LfjYa/c/o, BY 19m/9K Feb. 27, 1945. A, L HUCK 2,370,404

TEMPERATURE RESPONSIVE CONTROL MECHANISM Filed NOV. 10, 1941 3Shets-Sheel'. 3

ENT BY Qffa J 75M 9K l Patented Feb. 27, 1945 Alfred J. Huck, St. Louis,Mo., assignor to Knapp- Monarch Company, St. Louis, Mo., a corporationot Missouri Application November 10, 1941, Serial No. 418,455

(Cl. 21B-19) 7 Claims- My present invention relates to a temperatureresponsive control mechansim, and its general object is to providemechanism of the character shown in Brosseau Patent No. 2,179,811,adapted for an oven type toaster as distinguished from one of the doortype.

One object of the invention is to provide temperature responsive controlmeans particularly suitable for use with appliances intended for use insuccessive operating cycles, the mechanism being comparatively simpleand inexpensive to manufacture.

Another object is to provide an arrangement oi elements in thetemperature responsive control mechanism which prevent any possibilityof recycling where the comparatively heavy current necessary foroperation of anl-oven type toaster is to be controlled by the mechanism.

Still a further object is to-provide a latch adjustment which eliminatesany strain on the bimetal latch actuator in the normal position of themechanism.

Still another object is to provide temperature responsive controlmechanism which may be set by moving a vertically movable bread carrierdownward to toasting position.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of,

my device whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims and illustrated in theaccompanying drawings, wherein:

Figure 1 is a side elevation ot a bread toaster with parts of the casingshown in section and showing my temperature responsive control mechanismapplied thereto;

extend upwardly therefrom to support an inner base plate I3. The innerbase plate I3 forms a support for end plates I4 between which aremounted heating elements HE. The heating rier I5 in properly alignedposition. Ordinarily, I

three of the heating .elements HE are provided with two of the breadcarriers I6 arranged one between each outer heating element HE and thecenter heating element.

For raising and lowering both ends of the bread carrier` I8 evenly, Iprovide a pair of c'rank arms I9'L formed on the ends of a bar 20. Thebar 20 is pivoted at 2I and the arms I9* are connected by links 22 withthe extensions Il and I3. The 'extension I8 passes through a slot 23 inone end of the casing I5, and has an operating handle 24 mountedthereon. Opposite the handle 24 a. stationary handle 25 is mounted onthe casing I5.

'I'he bread carrier I6 is normally held in raised position by a spring26 connected with the ex- 4 Figure 2 is an end elevation from the rightof Figure 1, part of the gure being taken on the section line 2'-2 ofFigure 1;

Figure 3 is a view showing certain parts in the lower right-hand cornerof Figure 1 in a difierent position;

Figure 4 is an electro-diagrammatic view showing the elements of mytemperature responsive control mechanism in relation to the heatingelement of the toaster and the current Supply: and

Figure 5 is an enlarged bottom plan view of my temperature responsivecontrol mechanism and a portion of the bottom of the toaster on which itis mounted.

On the accompanying drawings I have used the reference numeral I0 toindicate the base of an electrical appliance. A plurality Aof posts I2tension I 3 and with a stationary bracket 21. The bread carrier I6 ismoved downwardly by pressing down on the knob 24, thereby stretching thespring 26, as shown by dotted lines in Figure l, the spring effectingreturn movement automatically, as will hereinafter appear.

My temperature' responsive control mechanism, shown perhaps best inFigure 5, includes a base plate 28 having a supporting sheet of insulation 29 mountedthereon.` The plate 2i!v is adapted to be secured,as' by screws 30, to the inner base plate I3 of the toaster. A mainswitch, comprising leaf spring contacts 3I and 32, is mounted on thesupporting sheet 29, the spring 3I being adapted for connection with aline wire 33, and the spring 32 being connected to a heat bridge bracket34. Secured to the heat bridge 34 is a timer compensating element 35 ofbimetal and carrying a contact 36. The

contact 36 is normally engaged' with a. contact 31. The contact 31 iscarried by a leaf spring 33 mounted on a bracket 39. The bracket 39 alsocarries a timer element l4|) of bimetal, adapted at times to engage theleaf spring 3l to separate the contact 31 from the contact 38.

Carried by the bracket 34 is a bimetal element 4| constituting a latchactuator. Another bimetal element 42 is connected therewith, whichconstitutes a latch actuator compensator, as well as a means to operatea latch 43. 'I'he latch 43 is carried by a leaf spring 44 which, inturn, is carried by an ear 45 bent downwardly from the edge of the plate28. A latch adjusting screw 48 is carried bythe latch 43 and has aninsulating button 4| to be engaged at times by the element 42. The leafspring 44 serves also as a friction element to retain the adjustment ofthe screw 48 with relation to the latch 43.

'I'he latch 43 is normally retained by the leaf spring 44 against a stopear 48 extending downwardly from the plate 28. Another ear 49 is bentdownwardly from the plate 28 andv has a shouldered bolt 50 supportedthereon. A bread carrier lock 5| is pivoted on the bolt 50, and a latchrelease bar 52 is slidable thereon by reason of a sl'ot 53 of the barcoacting with the screw. The bar 52 also slidably coacts with a slot 54of the plate 28, the bar having an ear extended therethrough and bentover, as indicated at l55, to retain the parts 28 and 52 in slidablyassembled relation to each other. The latch release bar 52 is normallyretracted to non-releasing position by a spring 56.

The bread carrier lock 5|, as shown in Figures 1 and 3, has a hook at 51which is adapted to hook over a pin 58 extending from a downwardextension 59 of the bread carrier extension I8. In Figure 3 the breadcarrier lock has been moved nearly to its locking position. Suchmovement is eiected by an ear 60 of the extension 59 engaging the breadcarrier lock 5| at a point to the left of the pivot 58, as shown inFigure 3, when the bread carrier is moved downwardly to carry the breadinto position between the heating elements HE. Locking is effected bythe left end of the` lock 5| forcing the latch 43 outward, as shown, andnally permitting it to swing inwardly again to an obstructing positionabove the left end of the lock 5 I.

If it is now desired to release the bread carrier manually, the latchrelease bar 52 may be slid to the left against the bias of the spring 56by engaging a lmob 6| mounted thereon and projecting bread carrier isunlocked so that it rises, it permits the leaf spring 3| to springupwardly again to its initial position, thereby breaking the circuit.

'I'he electric circuit from the line wire 33 can accordingly be tracedthrough leaf springs 3| and 32 to the heat bridge bracket 34, and thenthrough the bimetal element 35, the contacts 36 and 31 and the leafspring 38 to the ear of the bracket 38 to which the bimetal 40 issecured. The current then passes through a single strip of resist anceribbon TH which constitutes a timing heater. and this ribbon, asindicated at 69, extendsto a terminal 10. The terminal 18 is connectedto one end of the heating element HE, as shown' diagrammatically inFigure 4, and the other end of the heating element is connected with aline wire 1|.

My control mechanism further includes a latch heater LH in the form of aresistance ribbon connected with the bracket 39 at one end and with thebimetal element 4| at the other end so that current through the latchheater LH will return through the bimetal element 4| to the heat bridgebracket 34 at certain times, as will hereinafter appear.

My present invention differs from that shown in the Brosseau patent inseveral respects. One difference resides in the use of the spring blade38 to carry the current instead of having the bimetal element 4D do so.Accordingly, the operation is as follows:

When the toaster is set for operation and current is flowing from linewire 33 through elements 3|, 32, 34, 35, 36, 31, 38, TH, 69, 10 and HEto 1 I, the heating element is in operation and the timing heater THeffects a gradual warping of the timing element 40 clockwise toeventually separate the contact 31 from the contact 38. Thereupon, thelatch heater LH is introduced into 0 the circuit as it was formerlyshunted by the from the end of the toaster casing l5. This will forcethe latch 43 toward the left to release the left end of the lock 5|, anda spring 62 will thereupon swing the lock to its original position. Thehook 51 on the lock will accordingly release the pin 58, therebypermitting the spring 26 to lift the bread carrier. y

I provide adjustment for my temperature responsive mechanism so that thetiming period can be regulated as desired, to secure any color of toast.This is accomplished by pivotally mounting the bracket 39, as at 63, andforcing its opposite end, by means of a spring 64, against an adjustingscrew 65. The adjusting screw 65 is threaded in a bracket 66 andterminates in an adjusting knob 61. Adjustment of the knob effectsswinging of the leaf spring 38 to a more or less tensioned position. f

At the same time that the bread carrier is lowered, it effects closureof the main switch 3|32 lin the following described manner:

The ear 6|! of the downward extension 59 engages an insulating plate 58on the leaf springV 3| and forces the leaf spring downwardly until itengages the leaf spring 32. Reversely, when the contacts 36 and 31. Thecurrent then flows from the heat bridge 34 through the bimetal element4| and the latch heater LH to the bracket 39. The heat of the heater LHwarps the latch actuator 4I counter-clockwise to engage the adjustingscrew 46 and unlatch the latch 43 with respect to the bread carrier lock5|. The bimetal element 42 permits resetting of the toaster for the nexttoasting operation immediately, since it warps clockwise a delayedperiod of time after the latch actuator 4| warps counter-clockwise dueto the flow of heat from 4| to 42, as described in the Brosseau patent.Also, in said patent the heat bridge bracket 34 carries heatl from theheater LH to the bimetal element 35 which acts as a timer compensator,warping clockwise upon heat ailecting it, both in response to heatacross the-heat bridge and a general rise of ambient temperature of thetoaster. Since the current is carried in my mechanism across the spring3l instead of through the timer element 40, the relatively heavy currentnecessary for an oven type toaster can be handled without danger ofrecycling, as in the Brosseau arrangement where separation of thecontacts equivalent to my contacts 36 and 31, would cut out current iiowthrough the timer element 40, thus permitting it to cool slightly, eventhough the timing heater TH is still in the circuit, and such coolingcauses an undesirable recycling. With my arrangement, however, thecurrent at no time passes through the timing element 40, and it isaccordingly always responsive to only the timing heater TH and not tothe full heating element current passing through the timer elementitself.

Another feature adapting the present invention for better operation isthe separation of the latch Il from the latch actuating bimetal element4| itself, so that normally it is spaced from the bimetal element l2andplaces no strain on it or the bimetal element 4|, regardless of atwhat position the adjusting screw 46 is placed. This is a factoryadjustment, whereas color adjustment bread carrier and openingof thecircuit through y the toaster. l

Some changes may be made in the construction and arrangement of theparts of my device without departing from the real spirit and purpose ofmy invention, and it is my intention to Y cover by my claims anymodified forms of structure or use oiF mechanical equivalents which maybe reasonably included within their scope without sacrificing any of theadvantages thereof.

I claim as my invention:

l. In a toaster of the class described, a normally open main switch,means for manually closing said main switch, a latch for latching saidmain switch in closed position, and means for releasing said latchcomprising a temperature responsive timer element, a timing heatertherefor operable while said main switch is closed, a leaf spring, acontact carried by said leaf spring, said leaf spring being engageableby said timer element, a second contact engaging said rst contact toby-pass current aroundl said timer element, a second heater and athermal motor actuated thereby for releasing said latch, said secondheater being rendered operable by said contacts when they are disengagedas a result of temperature generated by said timing heater affectingsaid timer element.

2. In an electric appliance adapted to be operated in one or a pluralityof successive cycles, a source of heat for heating Asaid appliance, acasing disposed in proximity to saidheat source so as to be heatedthereby, and control means located in said casing comprising a controlelement and a delay-action thermal motor for operating said controlelement in each cycle to control said heat source, manually operablemeans for adjusting the position of said control element with relationto said thermal motor to determine the action thereof in the initialoperating cycle of the appliance, a heater for said thermal motor tooperate the thermal motor only element when said contacts are engaged.

3. In an electrical appliance having an electrically operated elementand an energizing circuitfor the element, a main switch for closing thecircuit to energize the element. latch means for holding said switch incircuit-closing position and temperature responsive timing means foractuating said latch, means comprising a delay-action thermal motoradapted to move the latch means out of holding position and a thermalelement adapted to move the latch means toward holding position tocompensate for the overrun of said thermal motor, a heater for saidtemperature responsive timing means, and a thermal timer to operate'saidheating means,=said thermal timer being responsive to only the heat ofsaid heater and ambient toaster temperature.

4. In an electric appliance adapted to be operated in one or a pluralityof successive cycles, a source of heat for heating said appliance, acasing disposed in proximity to said heat source so as to be heatedthereby, and control means located in said casing comprising a thermalmotor operated in each cycle to control said heat source, means forautomatically modifying the action of said thermal motor in successiveoperations of the appliance to compensate for variations in thetemperature of said casing, said last means including a heater for saidthermal motor, said motor being arranged relative to said heater so thatthe heat of the heater eiIects operation of the motor only after thecompletion of an operating cycle of the appliance, a timer element, atimer heater therefor, said timer element being responsive to said timerheater and to ambient appliance temperature only, and means whereby saidtimer heater effects movement of said timer element to position forenergizing said firstA heater.

5. In a toaster adapted to be operated at intervals in quick succession,a bread carrier. a control switch for the toaster, said bread carrierbeing operable to close said control switch, and timing means f oropening said control switch comprising a delay-action thermal motorbendable in one direction for opening the switch, a heater for operatingsaid thermal motor, and energizing means for said heater, saidenergizing means comprising a thermal timer including a bimetal timingelement and a leaf spring, contacts for controlling said heater with thecurrent passing through said spring and by passing said timing element,said timing element being engageable at the end of the timing periodwith said spring to operate said contacts.

6. In an electrical toaster having an electrically operated heatingelement and an energizing circuit for the heating element, a breadcarrier, a main switch for closing the circuit to energize the heatingelement when the bread carrier is moved to toasting position, latchmeans for holding said switch in circuit-closing positionyandtemperature responsive timing means for actuating said latch meanscomprising a thermal motor adapted to move the latch means out ofholding position, a heater for said thermal motor, a thermal timer tooperate said heater, and a second heater for said thermal timer'incircuit with said main switch, said thermal timer being responsive toonly the ambient toaster temperature and heat of said second heater tothereby continue in rst heater energizing position after reaching suchposition and until said rst heater effects movement of said thermalmotor to position releasing said latch and thereby opening said mainswitch to deenergize said second heater.

7. In a toaster of the class described, a vertically movable breadcarrier, a normally open switch, a spring retaining said -bread carrierin raised position, said bread carrier being manually lowerable forclosing said switch, a lock element for said bread carrier having a hookto engage the bread carrier when in lowered position, a Vlatch forlatching said lock element, and means for releasing said latchcomprising a temperature responsive timer element, a. heater thereforoperable while said switch is closed, a leaf spring adjacent said timerelement, a contact carried

